Implements such as are used in agriculture and various industries such as mining, road construction and maintenance, and the like include a wide variety of sizes and configurations. Implements such as combines, swathers, sprayers, road graders, earth movers, and the like are commonly self-propelled, with the engine, drive system, and operators station incorporated into the implement itself. Implements such as air seeders, cultivators, discs, grain carts, mowers, and the like are more commonly towed behind a tractor. Some implements are configured to be mounted directly on a tractor instead of being towed behind, such as snowplows mounted on the front end of a tractor, mowers mounted under a middle portion of the tractor, and a wide variety of implements mounted to the arms of a three point hitch system commonly incorporated on the rear end of tractors.
Some self-propelled implements have comprised a drive unit, which includes the engine, drive train, and operator's station, and different implements which can be mounted to the drive unit. For example Versatile Manufacturing Company of Winnipeg, Manitoba, Canada manufactured the Versatile™ 103 which included a drive unit with a swather header and a spraying assembly which were mountable to the drive unit.
Also the advent of very accurate external positioning systems using global positioning satellites (GPS) and the like has more recently led to the development of robotic agricultural vehicles with no operators station. For example recently Amazonen-Werke of Hasbergen, Germany, has developed a robot vehicle for carrying various application modules along a field surface for identifying plants, testing soil compaction, nutrient deficiencies and the like. The robot is controlled by an external guidance system such as using GPS, or by a remote control device. Remote or GPS controlled driverless tractors are also known, such as manufactured by Autonomous Tractor Corporation of Fargo, N. Dak., USA.
See also for example United States Published Patent Application Number 2014/0216314 of Bourgault et al. which discloses a driverless self-propelled air seeder that is guided by a GPS or like external guidance system, and/or by a remote operator.